DUI Tests and Charges in Texas

A drunk driving conviction can cause devastating consequences for your life – like losing your job, your driver’s license, and, in some cases, your freedom. One of the pieces of evidence that prosecutors often present to prove their case is results from breath and blood tests. While many people regard these test results as definitive proof, the truth is that they are full of potential errors. No one should be convicted based on flawed science or sloppy procedures. It’s important to have an attorney who knows how to challenge these tests.

The flaws in breath tests

Pretty much everyone knows what a breath test is because it is one of the most common tools law enforcement uses in DWI cases. However, they are far from perfect. The machines can be inaccurate for many reasons. Unreliable results should never be the deciding factor in a criminal case, so it’s important to fight back against questionable results. Some possible issues include:

• Calibration and maintenance problems – Breathalyzers require routine maintenance and calibration to produce accurate results. If law enforcement officers aren’t servicing it properly, the machine can give inaccurate readings. It’s possible to seek the maintenance logs as a way to uncover issues that may call test results into question.
• Human error – A breath test is only as reliable as the officer administering it. If they don’t follow strict procedures (like observing the suspect for a set period beforehand), the results can be compromised. Rushed testing, improper instructions, or failure to account for external factors can make the entire test meaningless.
• Medical conditions and other interferences – Breath tests are supposed to measure deep lung air, but that doesn’t always happen. Conditions like acid reflux, diabetes, and even using mouthwash before the test can lead to falsely high readings. Something as simple as a burp can completely throw off the results.
• Environmental contaminants – Certain chemicals in the environment can interfere with breathalyzer readings. If you work around paint fumes, cleaning supplies, or industrial solvents, those vapors could be on your skin and clothing. These chemicals can cause a false positive. This is especially relevant for people in construction, auto repair, or other trade industries.

Blood tests: Not as reliable as they seem

Prosecutors might treat blood tests as if they are even more reliable than breath tests. However, these tests come with their own problems. From the moment the person administering the test draws the blood through the actual test, there are multiple opportunities for mistakes that could lead to inaccurate results.

• Collection and storage issues – Blood samples must be drawn under sterile conditions, stored at the right temperature, and handled carefully. If a sample is exposed to heat, stored too long, or handled improperly, it can produce an unreliable BAC reading.
• Chain of custody breakdowns – Every blood sample follows a chain of custody. Everyone who handles or moves the sample must track and document their interaction with the sample. If there are missing records, mislabeled vials, or unexplained handling gaps, the test results lose credibility. A break in this chain may be enough to challenge the prosecution’s case.
• Fermentation and contamination – Blood samples can actually generate alcohol if they aren’t preserved correctly. If the sample ferments due to poor storage or improper preservatives, the BAC reading may be much higher than it actually was at the time of the arrest.
• Lab mistakes – Even in professional labs, human error is common. Mislabeling, equipment malfunctions, and contamination can all skew results. Defense attorneys regularly uncover sloppy lab practices that call BAC results into question.

Fighting back against faulty test results

Even when a test says you were over the legal limit, this doesn’t mean you’re guilty. A solid defense requires digging into every detail of how these tests were conducted and whether they hold up under scrutiny. Your attorney may take steps to identify flaws in the process or results. Some tactics might include:

• Examining calibration and maintenance logs
• Challenging police procedures
• Considering outside factors
• Reviewing blood sample handling
• Requesting independent testing

The appropriate approach will depend on the facts in your case. It’s best to speak to an attorney as soon as possible to give them time to work on a case strategy to defend you.

Why it’s important to protect yourself if you’re facing drunk driving charges

Texas takes DWI cases seriously. You need to take them just as seriously. Remember that charges do not equal convictions. The state still has to prove its case beyond a reasonable doubt, and if its key evidence is flawed, its argument may fall apart.

Although many people assume that failing a breath or blood test means a guaranteed conviction, that’s simply not true. You can challenge DWI charges. It is sometimes possible to discredit test results. A strong defense strategy can mean the difference between a conviction, a dismissal, and other potentially less damaging consequences.

If you’re facing a DWI charge, don’t accept the prosecution’s evidence at face value. With the right legal defense, you can fight back and protect your future. Contact Mary Beth Harrell Criminal Defense and DWI Lawyers today to schedule a consultation and start taking action to defend yourself.